Internal combustion engine of the two-stroke cycle type



Rh 3, 1932- H. B. GREENING ET AL "1,846,031

INTERNAL COIBUSTION ENGINE OF THE TWO-STROKE CYCLE TYPE Filed Jan. 17, 1931 i I H'L- Im/enZOrl/er ark/.5. yrecn/ /ry.

Patented Feb. 23, 1932 UNITED STATES PATENT, OFFICE man) a. exams am) mums w. oannowax, or

'mrr'ron, on'ramo, cumin,

ASSIGNOBS '10 GALLOWAY ENGINEERING COMPANY LIMITED, HAMILTON,

ONTARIO, CANADA.

Application fled January 17, 1031." Serial no. 809326,

The princi al objects of this invention are, to enhancet e operative value of internal combustion engines of the two stroke cycle t e and particularly to obtain the maximum I e oiency in an engine of the dual c linder 11501-13 provided with a common com ustion The principal feature of the invention consists in the novel arrangement of the intake port in one of the pair of cylinders in relation to the exhaust port in the other, whereby the intake port is opened slightly later than the exhaust port and remains open for a period considerably greater than the exhaust 1 ext, whereby the maximum volume of comustible gas is placed within the cylinder.

In the accompanying drawlngs, Figure 1 is a longitudinal mid-sectional view of a dual cylinder structure having a common combus- 2 tion head and to which this invention has been applied.

Figure 2 is 8. dia am illustrating the relative movement of t e pistons and crank shaft.

Figure 3 is a diagram illustrating the rela tive value of the port openin s.

In the ordinary practice in the construction of engines of the dual cylinder combined combustion head type wherein one piston travels slightly in advance of the other it is found that when the intake and exhaust ports are arranged a corresponding distance from the outer end of the cylinders, or the same dis tance from the respective bottom dead centres of the crank, the pressure within the cylinder drops to atmosphere or supercharger pressure very rapidly once the exhaust opens.

It has been found that by placing the intake port in such a position that it will open slighty later than the exhaust port the combined effect of the inertia of the exhaust and the scavengin effect of the incoming gases causes the cylin ers to be cleared quite rapidly of the exhaust gases. This permits a comparatively early closing of the exhaust port and to obtain the best efiicicncy it is desirable that the intake should remain open for a considerable period after the exhaust closes so as to obtain the full benefit of the volume of fuel directed thereto by a blower or superchanger and also to obtain the full benefit of the natural effect of flow under atmospheric pressure to-the interior of the cylinder following the closing'of the exhaust port. 1

As shown in the accompanying drawings, cylinders 1 and 2 are connected by a common combustion head 3.

The intake port 4 is arranged a shorter distance X from the head end of the cylinder than is the distance Y of the exhaust port 5 from the head end of-the cylinder.

As illustrated in the diagram Fig. 3 the point of o enin E O of theexhaust 1s in advance of t e polnt of opening I O of the intake by the angle A and this angle is less than the angle B between the point E G of the closing of the exhaustend the point I G of the closing of the intake. I

This occurs when the sum of the distance X of the top of the intake port below the top of the cylinder plus the height of the piston above the wrist pin X plus the distance from the wrist pin to the crank pin L is less than the corresponding dimensions for the exhaust side, and the angle A is in like proportion less than the angle B.

at we claim as our invention is 1. An internal combustion engine in which a. pair of c linders one having the intake port and the ot er the exhaust port are connected by a common combustion head and the piston of the exhaust cylinder leads the piston of the intake cylinder, said intake port being of a width to maintain an open port until after the exhaust port is closed.

2. An internal combustion engine in which a pair of cylinders are connected by a common combustion head and one cylinder is provided with an intake port and the other with an exhaust port and the pistons are arranged with the one in the exhaust cylinder leading, said ports being so proportioned and arranged that the distance from the head end of the cylinder to the top of the intake port plus the distance from the head end of the piston to the wrist pin center plus the distance from the wrist pin center to the crank pin is less than thedistance from the cylinder head to the top of the exhaust port plus the distance from the piston head I the wrist to the wrist pin center plus the distance from pm to the crank pin.

3. A. dual cylinder two-c cle engine havin a common combustion ead and the int e port arranged in one cylinder and the exhaust port arranged in the other, pistons operating in said cylinders with the one in the exhaust cylinder leading, the to of the intake port hem?1 closer to the cylin er head than the top of t e exhaust port and the bottom of said intake port being spaced from the top thereof so that the intake piston cooperates with the intake port to close the intake port a considerable period of time following the closing of the exhaust port by the exhaust piston permittin the entrance of the maximum volume of uel to the cylinder.

HERALD B. GREENING. JAMES W. GALLOWAY. 

